1. Field of the Invention
This invention relates generally to communication networks, and more specifically to a system and method for transferring information among users communicating over a communication network.
2. Related Art
Prior to the introduction of the Integrated Services Digital Network, or ISDN, the traditional telephone system required one signaling channel for each voice channel. Thus, to support 23 conversations, the traditional non-ISDN telephone system required 23 voice channels and 23 signaling channels for a total of 46 channels. In contrast, ISDN requires 24 channels total to support 23 conversations. Traditional telephone systems having one signaling channel for each voice channel are said to use in-band signaling. ISDN systems having a single signaling channel for multiple conversation channels are said to use out-of-band signaling.
The ISDN has two transmission components: primary rate interface (PRI) and basic rate interface (BRI). Primary rate interface typically carries twenty-three bearer channels and one signaling channel. In other words, the primary rate interface can support twenty-three simultaneous conversations using a single signaling channel. Basic rate interface carries two bearer channels and a data channel.
User-to-user signaling service exists for users who subscribe to the primary rate interface. With the primary rate interface, twenty-three voice channels can be voiced by a single signaling channel. With user-to-user service the twenty three calls can independently send data between the users using just one signaling channel.
The ISDN signaling channel is directed by an originating inter-exchange carrier switch to a first signal transfer point. The signaling channel is then transferred via a signaling network such as the SS7 signaling network to a second signal transfer point. The signaling channel information is then transferred to terminating inter-exchange carrier switch.
Unfortunately, when a user wishes to send a large block of user data, the signal transfer points can become overloaded as a result of the excessive data flow through the signaling network.